Method and apparatus for parallelizing staple fibers fed to a spinning chamber

ABSTRACT

A STREAM OF STAPLE FIBER PASSING THROUGH A FEED DUCT IS SURROUNDED BY AN ENVELOPING AIR JACKET SO THAT THE FIBERS ARE CONCENTRATED TOWARDS THE CENTRAL AXIS OF THE DUCT. THE AIR JACKET IS FORMED BY DRAWING AN ADDITIONAL SOURCE OF AIR INTO THE DUST THROUGH AN ANNULAR FREE ZONE.

United States Patent Office 3,557,543 Patented Jan. 26, 1971 ,910 Int.Cl. G01h 7/00,- D01g 23/08 US. Cl. 57-58.95 15 Claims ABSTRACT OF THEDISCLOSURE A stream of staple fiber passing through a feed duct issurrounded by an enveloping air jacket so that the fibers areconcentrated towards the central axis of the duct. The air jacket isformed by drawing an additional source of air into the duct through anannular free zone.

This invention relates to a method and apparatus for introducing staplefibers in parallel relation into a spinning chamber of an open endspinning device. More particularly, this invention relates to a methodand apparatus for placing staple fibers in parallel.

Heretofore, feed devices have been known for feeding staple fibers intoa spinning chamber possessing a rotating fiber collecting surface of anopen end spinning device. In some instances, the individual fibers havebeen accelerated through narrowing feed ducts into the spinning chambersto speeds approximately the circumferential speeds of the fibercollecting surface in order to straighten the otherwise curved fibersand to bring the fibers into the direction of flow of the air stream.

This fiber parallelization for feeding into the fiber collectingsurface, while being advantageous as such, however, has the disadvantagethat for aerodynamic reasons the distances over which the fibers areaccelerated must be relatively long, i.e. the taper of the narrowingfeed duct must be feeble or of minimum value if vortex formation is tobe suppressed. Also, the ratio of cross-section areas of the duct at theentry and at the exit must be chosen according to the ratio of input andoutput speeds of the fibers. The exit cross-section area, on the otherhand, cannot be reduced below a certain minimum for manufacturing andtechnological reasons. Thus, the dimensions of entry and exitcross-section areas and of the length of the duct require determinationto a large extent after the ratio of speeds is chosen. This severelylimits freedom of design. Further, as the fibers become distributedacross approximately the whole duct cross-section area, a furtherdisadvantage is noted in that the fibers in proximity of the duct wallsbecome decelerated by the duct wall boundary layer which increases inthickness in the direction of the flow of the medium. Thus, any fiberstraightening and parallelization which is achieved is subsequentlyimpaired.

Accordingly, it is an object of the invention to keep the fiber streamaway from the interior walls of a feed duct.

It is another object of the invention to concentrate the fiber stream inthe center of an acceleration duct.

Briefly, the invention provides a method and apparatus of concentrating,parallelizing and accelerating a flow of staple fiber within aconcentrated cross-sectional area within a feed duct for delivery to afiber collecting surface in an open end spinning device.

The method comprises the steps of transporting a stream of staple fibersthrough a feed duct in an air stream under a suction force and ofvigorously accelerating and pushing the staple fiber away from theinterior walls of the feed duct by the use of an additional air streamdirected into the interior of the duct from the extreior. The additionalair stream is directed into the feed duct at an intermediate free zoneof the duct so as to circumferentially envelop the stream of staplefibers within a jacket or coat of air which is substantially free ofstaple fiber.

The apparatus for implementing the method includes an acceleration ductwhich is positioned between a fiber input point and a spinning chamberheld under vacuum. The duct which serves to feed a stream of staplefibers from the input point to the spinning chamber is interruptedwithin a short free or open zone so that exterior air can be drawn intothe confines of the feed duct substantially circumferentially about thestream of staple fiber passing through the duct so as tocircumferentially envelop the staple fiber stream. The free zone isfurther in communication with a suitable chamber about the feed ductwhich contains a supply of air at a higher pressure than the interior ofthe duct. The additional air which is drawn into the feed duct from thefree zone serves to concentrate the staple fibers towards the center ofthe feed duct while maintaining the boundary layer along the interior ofthe feed duct substantially free of staple fiber. The additional airalso serves to accelerate the staple fibers while allowing the duct tohave substantially the same size inlet and exit openings for difierentinlet and exit speeds for the staple fibers.

These and other objects and advantages of the invention will become moreaparent from the following detailed description and appended claimstaken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a cross-sectional view of an open end spinning deviceincorporating an apparatus according to the invention;

FIG. 2 illustrates a top view of the structure of FIG. 1;

FIG. 3 illustrates a cross-sectional view of a modified apparatusaccording to the invention;

FIGS. 4 and 5 each illustrate a cross-sectional view of other modifiedfeed ducts according to the invention; and

FIG. 6 illustrates a further modified feed duct according to theinvention.

Referring to FIGS. 1 and 2, a sliver 1 of staple fibers is supplied atan input point to a needled opening roll 2 of known constructionrotatably mounted within a substantially enclosed chamber of a housing.The roll 2 serves, under ideal conditions, to take 01f individual fibers3 from the sliver 1 and to transfer the fibers 3 to an air stream whichenters the housing axially through an opening 4 and then flows radiallyof the roller chamber to a feed duct 5 within the housing. The feed duct5 is in.

communication with a spinning chamber -6 in the housing which possessesa rotatable fiber collecting surface 7 mounted on a rotor 8. The rotor 8serves to rotate the collecting surface 7, as is known, at highrotational speeds sufficient to generate a vacuum.

Jan. 26, 1971 w, KRAUSE 3,557,543

METHOD AND APPARATUS FOR PARALLELIZING STAPLE FIBERS FED TO A SPINNINGCHAMBER Filed May 26, 1969 v I I A" a! 2 Fig. 1

i INVEN'IOR. HANS w.- Rpm/6E point and said free zone forpre-accelerating the stream of staple fibers prior to passage throughsaid free zone.

11. An apparatus as set forth in claim 8 wherein said feed duct has atapered second section between said free zone and the spinning chamberfor further accelerating the stream of staple fibers after passagethrough said free zone.

12. An apparatus as set forth in claim 8 wherein said feed duct is of aconstant cross-section between the input point and said free zone.

13. An apparatus as set forth in claim 8 wherein said feed duct is of aconstant cross-section between said free zone and the spinning chamber.

14. An apparatus as set forth in claim 8 wherein said feed duct has apair of said free zones in spaced relation to each other therein forstepwise acceleration of the stream of staple fibers.

15. An apparatus as set forth in claim 8 wherein said free zone ispositioned intermediately of said feed duct,

and wherein said feed duct has a section between said free zone and thespinning chamber, said section having a funnel-like end overlapping saidfree zone.

References Cited UNITED STATES PATENTS I 3,355,869 12/1967 Vorisek57-58.95 3,360,917 1/1968 Kubovy et a1 57-5895 3,440,812 4/1969 Stary eta1 57-58.95X 3,445,993 5/1969 Vorisek 57-58.95X 3,455,097 7/1969Raj-noha et al. 57-5895 3,487,626 1/1970 Rajnoha et al 57-5831 3,501,9073/1970 Tabata et al. 5758.89X

DONALD E WATKINS, Primary Examiner US. Cl. X.R. 57-156

